V.F. Nikitin

Irregular traffic flow on a ring road

Abstract A model of irregular single-lane traffic flows on a ring road is proposed, with a number of fundamental differences from those traditionally examined in continuum mechanics. Even in the simplified version of the examination of single-lane traffic, the model enables a correct qualitative and quantitative description to be obtained of the conditions for ensuring maximum carrying capacity and for the occurrence and evolution of traffic jams on roads.

Numerical Simulations of Gaseous Detonation Propagation Using Different Supercomputing Architechtures

The aim of the present study is to calculate the process of detonation combustion of gas mixtures in engines. Development and verification of 3D transient mathematical model of chemically reacting gas mixture flows incorporating hydrogen was performed. Development of a computational model based on the mathematical one for parallel computing on supercomputers incorporating CPU and GPU units was carried out. Investigation of the influence of computational grid size on simulation precision and computational speed was performed. Investigation of calculation runtime acceleration was carried out subject to variable number of parallel threads on different architectures and implying different strategies of parallel computation.

Nonequilibrium processes in meta-stable media⋆

Abstract.Meta-stable systems are those staying in the local equilibrium state: being slightly deviated from it they return to the equilibrium, but in case deviation surpasses a critical value those systems fall down to another equilibrium state. Chemically reacting gaseous mixture provides a typical example of a meta-stable system. The paper is aimed at numerical and experimental investigation of detonation initiation in hydrogen-air mixtures due to focusing of a shock wave reflected inside a wedge. Both numerical and experimental investigations were conducted. Comparison of numerical and experimental results made it possible to validate the developed 3D transient mathematical model of chemically reacting gas mixture flows incorporating hydrogen-air mixtures. Kinetic schemes and turbulence models were improved based on comparison of numerical and experimental results. Several different flow scenarios manifest in the reflection of shock waves all being dependent on the incident shock wave intensity: reflection of the shock wave with lagging behind the combustion zone, formation of a detonation wave in reflection and focusing, and intermediate transient regimes.Graphical abstract